As Good As A Jenvey?

[Gtiracer 0]

Hi guys, im always wary about buying performance modifications from ebay, i've seen this item at a smaller cost and as im due to get throttle bodies shortly, would help me out and would appreciate your help.

 

Check out THIS JENVEY MANIFOLD and tell me if you think its ok. To me it seems to have all the normal and correct fittings to the jenvey item (although painted red) but everything else looks ok, yet he's selling for £115 as opposed to jenveys RRP of £180. Something seems to be wrong. Or maybe i just don't know a good deal when i see one? I dunno, please help us identify whether its the correct one or not

 

Cheers (again! )

[Daz_C 8 1 Cars]

mmmmmmmmm

Looks pretty poor to me although it will do the job.

Thats Not a Jenvey Manifold and nor does he say it is. The seller is Midland Performance Centre (chav central) part of Ashley Exhausts.

Don't know what the pro's or cons are of it being made of mild steel if anythink at all but I recon you could make that yourself for about £20 !

I know the Jenvey ones are expensive at £180 but so is £115.

So would you like to pop the bonnet on your Pug and see this

 

 

or this

 

 

I think the first one looks longer than the Jenvey which may cause you some issues with fitting boddies behind the slam panel but that may just be the picture. You would have to ask him what length it is.

Edited December 24, 2006 by Daz_C

[Bonzai 2]

as said £115 is hardly cheap. I bought 2 inlet manifolds suitable for 45's, the jenvey/longmans was £100, the bastardised gti6 inlet was £160 i think. SO basically, keep an eye on the second hand market and you never know what might just turn up.

 

 

BTW, im not hoarding them, i just dont know which one to use as yet as both ahve their advantages

[Jer309GTi 3]

On the red one there are two servo take-off points. I suppose the idea is to put both these into a tee-piece, and then connect the servo hose to this? Would this give a stronger (or more even?) vacuum having two take off points?

[boombang 2]

Yes it would, but more importantly it would give a more stable signal for if you were to use a MAP sensor.

[M3Evo 0]

Yeah, the more vacuum takeoffs the better really.

 

I used to have just the one on mine and it made both my boost gauge and MAP sensor go absolutely mad so I ended up tapping all the throttles.

 

We tapped each cylinder on Stu's to even things out but I guess being a 4pot there's no overlap of cylinders drawing breath so it's still a bit wobbly (as is mine come to think of it)

[Sandy 191]

Half the point of seperate TB's is to isolate the cylinders on the inlet side. Connecting them all up again defeats that.

[M3Evo 0]

Yeah but compared to a plenum, the areas for the air to pass between cylinders are tiny!

 

I've got 6mm pipes going to 4mm tappings in the throttles which on a 6cyl engine still makes the vacuum gauge bobble around whereas on a plenum intake it'd be pretty much rock steady at idle.

 

You can use it for things like idle control too if they're all connected. My M3 engine has a big air rail next to the fuel rail for just this purpose (and probably to smooth out any imbalances too)

[TB_205GTI 1]

Yeah but compared to a plenum, the areas for the air to pass between cylinders are tiny!

 

I've got 6mm pipes going to 4mm tappings in the throttles which on a 6cyl engine still makes the vacuum gauge bobble around whereas on a plenum intake it'd be pretty much rock steady at idle.

 

Use a small petrolfilter on the hose to the gauge - it will act as a buffer. This is way better than connection them all six together

[PumaRacing 2]

On the red one there are two servo take-off points. I suppose the idea is to put both these into a tee-piece, and then connect the servo hose to this? Would this give a stronger (or more even?) vacuum having two take off points?

 

They've got them on the wrong runners. With a 1-3-4-2 firing order you want vacuum advance or servo connections taken from cylinders that don't fire consecutively. That means 1 and 4, or 2 and 3, or all four. They've got them on 1 and 3. Very silly.

[PumaRacing 2]

Half the point of seperate TB's is to isolate the cylinders on the inlet side. Connecting them all up again defeats that.

 

Connecting little vacuum advance or servo pipes to runners doesn't make a scrap of difference to the pulse tuning of the main air flow. It's 'separate' btw.

[M3Evo 0]

Use a small petrolfilter on the hose to the gauge - it will act as a buffer. This is way better than connection them all six together

 

Did have a restrictor in the signal line which did help a lot, but the gauge still rattled at idle and light load and the MAP signal on the datalogger wass all over the place!

 

Really don't see the problem with having all the pots connected together, if it's good enough for BMW it's good enough for me

 

It's gotta be kinder to the servo too I'd have thought.

[Sandy 191]

Connecting little vacuum advance or servo pipes to runners doesn't make a scrap of difference to the pulse tuning of the main air flow. It's 'separate' btw.

Probably, but alot of people use 10-16mm pipes.

 

Give it up, it's Christmas.

Edited December 24, 2006 by sandy309

[Matt Holley 11]

I was looking at maniflods on ebay a few days ago and found that exact manifold also brand new for £85

 

I think I am going to keep looking for a longman manifold though

 

EDIT I found it, it looks very similer but is a differant colour item number 220061798162

Edited December 26, 2006 by matt holley

[welshpug 1,657]

I was looking at maniflods on ebay a few days ago and found that exact manifold also brand new for £85

 

I think I am going to keep looking for a longman manifold though

 

EDIT I found it, it looks very similer but is a differant colour item number 220061798162

 

 

that one's purple and shorter

 

theres 2 specific carb manifolds with gaskets ob ebay for not much more, better to get these.

[M3Evo 0]

Surely it would suit either 40mm or 45mm and not both thinking about it?

[PumaRacing 2]

Yeah but compared to a plenum, the areas for the air to pass between cylinders are tiny!

 

I've got 6mm pipes going to 4mm tappings in the throttles which on a 6cyl engine still makes the vacuum gauge bobble around whereas on a plenum intake it'd be pretty much rock steady at idle.

 

You can use it for things like idle control too if they're all connected. My M3 engine has a big air rail next to the fuel rail for just this purpose (and probably to smooth out any imbalances too)

 

Still far too big even with all the runners connected. To get good signal but without pulsations from independent runners you need to damp the flow. What that requires is drillings about 1mm diameter somewhere in each line. If you have a lathe then the easiest way is to drill lengths of brass or aluminium about an inch long and stick them in the lines. Alternatively you can file a flat on a bit of bar and push that up each line or even crimp the lines almost shut.

 

The other way to damp flow pulsations is to use volume which is what a plenum does anyway. Connect the small pipes from the runners to a large container and then take the feed off that to the dizzy or brake servo.

 

I had to apply the same principles when I was designing my flowbench. To get a steady reading on the manometers during unsteady flow conditions I made a set of 2 inch long brass connectors with 1mm drillings through them (not easy to drill that small for so long) and used those to join sections of the manometer tubing. Problem solved and accuracy within 1% of true flow based on calibration plates.

[M3Evo 0]

For my damper to the MAP sensor, I squashed a bit of copper brake pipe right down and stuck it up the pipe. The trace is still a little bit bobbly on idle but the sensor's only called into play for pressures over atmos where it smooths out a fair bit, the ECU's set to ignore it when there's vacuum.

 

Would the servo charge up (down) quick enough with say just 4No. 1mm tappings?

[Dream Weaver 2]

I have some brand new Longmann manifolds that you can have for £125. They have been ported by QEP as far as I know. I bought them from Dino, and they are still sat down with him in North London as well until I can arrange to pick them up.

 

You can have them if you like?